Cardiovascular disease accounts for nearly fifty percent of deaths in both the developed world and in developing countries. The risk of dying from heart disease is greater than the risk from AIDS and all forms of cancer combined. Cardiovascular diseases cause approximately 12 million deaths in the world each year. It is the leading cause of death in the US, killing approximately 950,000 people each year. It also accounts for a significant amount of disability and diminished quality of life. Indeed, approximately 60 million people in the US alone have some form of heart disease. A great need, therefore, exists for the advancement of devices, methods, systems, and procedures to cure, treat, and correct a wide variety of forms of heart disease.
Normal heart function primarily relies upon the proper function of each of the four valves of the heart, which allow blood to pass through the four chambers of the heart. These four valves have cusps or leaflets, comprised of fibrous tissue, which attach to the walls of the heart. The four chambers of the heart include the right atrium and left atrium, the upper chambers, and the right ventricle and left ventricle, the lower chambers. The four valves, controlling blood flow in and between the chambers, include the tricuspid, mitral, pulmonary, and aortic valves. Heart valves are complex structures that consist of moveable leaflets that open and close the valve. For example, the mitral valve has two leaflets and the tricuspid valve has three leaflets. The aortic and pulmonary valves have three leaflets that are more aptly termed “cusps,” as they have a half moon shape.
The cardiac cycle involves the pumping and distribution of both oxygenated and deoxygenated blood within the four chambers. Oxygenated blood, enriched by the lungs, reenters the heart into the left atrium or left upper chamber. The mitral valve, a one way inflow valve, then directs the oxygenated blood into the left ventricle. The contraction of the left ventricle pumps the oxygenated blood through the aortic valve, into the aorta, and into the blood stream. When the left ventricle contracts the mitral valve closes such that the oxygenated blood passes into the aorta. Deoxygenated blood returns from the body via the right atrium. This deoxygenated blood flows through the tricuspid valve into the right ventricle. When the right ventricle contracts, the tricuspid valve closes and the deoxygenated blood is pumped through the pulmonary valve. Deoxygenated blood is directed to the pulmonary vascular bed for oxygenation, and the cardiac cycle repeats itself.
Mitral valve regurgitation is one the most prevalent heart disease conditions, which has many levels of severity. After 55 years of age, some degree of mitral regurgitation is found in almost 20% of men and women who have an echocardiogram. Mitral valve regurgitation, or mitral regurgitation, is a condition in which the mitral valve doesn't close tightly. It results from the failure of the mitral valve leaflets to completely close when the left ventricle contracts, resulting in the flow of blood back into the left atrium due to an overworked left atrium. This allows blood to flow backward in the heart which in turn can lead to serious heart conditions such as congestive heart failure and serious heart rhythm irregularities (arrhythmias). Mitral valve regurgitation is also a progressive condition that, if not corrected, can be fatal.
Also, approximately 40% of patients having some form of surgery in an attempt to correct mitral valve regurgitation end up with either 1+ or 2+ regurgitation measurements. While this may result in improved regurgitation characteristics, the future for these patients can involve additional surgery as their improved regurgitation characteristics will typically degrade over time as 1+ or 2+ regurgitation can negatively affect heart valve functionality.
The function of an atrioventricular valve, like the mitral valve, involves the complex interaction of numerous components, including the leaflets, chordae tendineae, and papillary muscles. If one of the components or functions of the complicated interaction fails, then mitral valve regurgitation can result. For example, excess leaflet tissue, inadequate leaflet tissue, or restricted motion of the leaflets can lead to mitral regurgitation.
Techniques currently exist to assist in correcting the shape of a mitral valve to control the geometries of mitral valve shape. For example, one conventional technique includes surgically reshaping the ventrical with extensive surgical manipulation. Another conventional technique involves reshaping the geometry of the annulus of the ventrical with a ring or other annuloplasty device. Another conventional device is the Coapsys Device manufactured by Myocor, Inc. (Maple Grove, Minn. USA) and described in U.S. Pat. Nos. 6,332,893 and 7,077,862.
These conventional techniques, while serving their respective purposes, do posses drawbacks. For example, certain of these conventional techniques, can at times, require extensive surgery which can increase possible associated risks to patients. Also, these techniques do not utilize an atrioventricular valve's papillary muscles to assist in reshaping valve geometry by apically adjusting a papillary muscle to control valve regurgitation. Further, these conventional devices do not enable fine tuning adjustments to be made on a beating heart to control, reduce, and eliminate blood regurgitation in atrioventricular valves.
Accordingly, there is a need for devices and methods to control the position of papillary muscles relative to an annulus of an atrioventricular valve. In addition, there is a need for devices and methods to reposition a papillary muscle using a positioning device to assist in controlling, reducing, and eliminating blood regurgitation. Still yet, there is a need for devices and processes enabling apical adjustability of positions between papillary muscles and an annulus of an associated atrioventricular valve. There is still yet a further need for devices and methods enabling fine tuning adjustments to be made on a beating heart to control, reduce, and eliminate blood regurgitation in atrioventricular valves. It is to the provision of such papillary muscle positioning devices, systems, processes, and methods that the various embodiments of the present invention are directed.